Low frequency noise and current–voltage measurements in several heavily doped polysilicon resistors of varying geometry and bothpandntype, and over a limited range of temperatures from −60 to 50 °C were conducted for the first time. We found that the noise inp-type polysilicon was independent of temperature, but not then-type polysilicon. For thep-type resistors, linear current–voltage characteristics were observed, and the relative noise spectral density was independent of bias and inversely proportional to frequency. For then-type resistors, linear current–voltage characteristics were observed, and the relative noise spectral density was independent of bias. Finally, the normalized noise level in the linearn-type resistors was almost an order of magnitude lower than for thep-type resistors. We believe that this difference is becausen-type dopants segregate to the grain boundaries, thus passivating some of the traps there. Boron(p-type dopant), on the other hand, does not segregate to the grain boundaries, leaving more unpassivated grain-boundary traps which capture and emit more carriers, resulting in more low frequency noise.